Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: 10-1-2007)


Herring Gull plumages:

hg 1cy July
hg 1cy August
hg 1cy September
hg 1cy October
hg 1cy November
hg 1cy December

hg 2cy January
hg 2cy February
hg 2cy March
hg 2cy April
hg 2cy May
hg 2cy June
hg 2cy July
hg 2cy August
hg 2cy September
hg 2cy October
hg 2cy November
hg 2cy December

hg 3cy January
hg 3cy February
hg 3cy March
hg 3cy April
hg 3cy May
hg 3cy June
hg 3cy July
hg 3cy August
hg 3cy September
hg 3cy October
hg 3cy November
hg 3cy December

hg sub-ad January
hg sub-ad February
hg sub-ad March
hg sub-ad April
hg sub-ad May
hg sub-ad June
hg sub-ad July
hg sub-ad August
hg sub-ad September
hg sub-ad October
hg sub-ad November
hg sub-ad December

hg ad January
hg ad February
hg ad March
hg ad April
hg ad May
hg ad June
hg ad July
hg ad August
hg ad September
hg ad October
hg ad November
hg ad December

Herring Gull C528J 2cy (argentatus), August 11 2002, Tampere, Finland (61.31N,23.43E).

A 2cy argentatus, trapped and ringed as 2cy bird orange C528J, today August 11 2002 in Tampere Finland (61.31N,23.43E). A bird with a pale iris, arm-span: 415 mm. 
The complete moult is well underway with most wing-coverts and the inner primaries moulted to second generation. The outermost primaries P9-P10 are still juvenile. P1-P6 are fully grown second generation flight-feathers. The primary moult score is 36. The outermost secondary S1 has been replaced for a second generation feather. The next three or four secondaries are missing and from about S5 inwards the complete secondary-row is still juvenile.
The tail-feathers are moulted centrifugal, with the inner rectrices shed first and two moult waves running outwards. In this bird, C528J, the outer rectrices are still juvenile. The inner tail-feathers are renewed and show a barred pattern. In many argentatus, the second generation tail-feathers show only a narrow tail-band, which is sometimes rather ill-defined. 
The upper tertials and most of the wing-coverts are replaced for second generation feathers. The only wing-covert still to be replaced can be found in the upper row of the lesser coverts, of which feathers are still missing in the carpal edge. All scapulars have been replaced by second generation feathers, including the scapulars in the lowest row.

By August, the warm brown tones of the first moulted wing-coverts (inner greater coverts and median coverts) are faded to plain white, leaving a contrasting barred pattern on the wing-coverts. On average, 2cy argentatus is more contrastingly patterned than same aged 2cy argenteus, especially regarding the pattern on the central greater coverts. However, some argentatus (like this individual) are distinct "washed out" brown, showing the common vermiculated pattern of 2cy argenteus
The last moulted coverts are the central greater coverts and outer lesser coverts, replaced by mid-August. From mid-August onwards, 2cy argentatus start the partial autumn moult, starting again to drop the upper tertial and inner greater and median coverts.

In the table below, the primary moult scores of 2cy August argentatus in Finland can be read:

2cy argentatus in August, Tampere landfill, Finland, August 10 2002, 10:00-12:00 h.
  P5 new P6 new P7 new P8 new total old:
P9 old 1 8 8 - 17
P10 old - 15 42 2 59
no old - - 59 4 63
total new: 1 23 109 6 139
old primaries: m = 9.3, SD = 0.69, n = 139.
new primaries: m = 6.9, SD = 0.47, n = 139.